Communication between a power source or a power distribution unit (PDU) and a load device can provide valuable information which can be used to audit, manage, and operate a power distribution system more efficiently. It can be useful for a power supply to provide communication to the load device for a variety of reasons. As an example, the power supply can provide data communications to the load device that can be used for activation/deactivation and/or handshaking. As another example, the power supply can provide a signal that indicates a loss of input power, such as to warn the load device that it needs to prepare for an imminent loss of power.